1. Field of the Invention
The present invention relates to remote security systems, and more particularly to remotely activated disabling systems for prevention of the continued unauthorised use of a secured device.
2. Description of the Prior Art
The rising incidence of motor vehicle theft has resulted in various theft prevention devices which in one way or another increase the risk and thus reduce the efficacy of the theft. Most frequently the mechanism of theft detection is the mechanism of choice, and various alarm systems have been devised in the past which detect unauthorised intrusion and use. Along with the evolution of alarm systems a parallel development has been directed at mechanisms that disable the vehicle upon the detection of theft. These, for example, include variously concealed shut-off devices that disable a motor vehicle.
In typical form the vehicle is disabled after a period of unauthorised use, more or less automatically, and the possibility of a stranded vehicle in the center of a thoroughfare is an ancillary concern of all such disabling devices. Theft of a vehicle, however, is not the sole focus of concern. Rental agencies, leasing agencies, and sometimes the financing enterprise each have a direct interest in the continued use of the leased article, particularly when the various term provisions of the leasing, financing, or rental agreement have expired. In these circumstances the harsh consequences of automatic uncontrolled shut-down, and the consequent risks to the users are not desired, and some means for attenuation of the shut-down sequence are sought.
This attenuated method is particularly significant in settings that do not amount to an emergency. Unlike the exigency associated with vehicle theft, device shut-down for contractual reasons does not represent sufficient cause for any risk enhancement. The preference, therefore, is to acquire control over the article through judicial process, or by reposession, and not by methods justifying the risks associated with crime. Thus while the prior art is replete with devices that become effective following a carjacking, these techniques are not correct in a civil setting.
In the past the incidence of criminal taking has been the principal focus of attention in the art. Thus various interrogation and response techniques have been devised in systems directed to automatically control the criminal use of a vehicle. Examples of such prior art systems may be found in U.S. Pat. No. 5,370,201 issued on Dec. 6, 1994 to Inubushi; U.S. Pat. No. 3,646,515 issued on Feb. 29, 1972 to Vodehnal; U.S. Pat. No. 5,224,567 issued on Jul. 6, 1993 to Tomlinson; U.S. Pat. No. 5,293,527 issued on Mar. 8, 1994 to Sutton et al; U.S. Pat. No. 5,382,948 issued on Jan. 17, 1995 to Richmond; U.S. Pat. No. 5,287,006 issued on Feb. 15, 1994 to Carlo et al; and others. Each of the foregoing, while suitable for the purposes intended, either requires two way communication with the vehicle, or is rendered operative in an automatic mode. In both instances the device is simply disabled at whatever operating mode that is then effected.
The attenuated shut-down, necessary for a safe device disablement in a civl setting, is not attended in the foregoing prior art and it is such a technique accomodating this particular objective that is disclosed herein.